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1982 CB750C - High Idle after touching throttle

2857 Views 8 Replies 6 Participants Last post by  CBF
Hey all, I received the a set of carbs from eBay, cannibalized the original set and set up the new one on the bike.

Fired up instantly, few pops, but smoothed out after adjusting the rod with black knob at the "bottom" of the carbs.

Problem is, when I touch the throttle, it hangs at 3.5k- 4k RPM, and won't go down, choke kills the bike after a few seconds, so that works.

I've made sure there's a bit of slack on the throttle cable, and the others as well. No leaks, but it does smell rich. The Primary Screws have all been equalized to ~3 turns out. Compression is great hovering around 135 (all 4).

This is my first carb rebuild, and at first I actually misplaced the primary and secondary jets, but that has since been fixed.

Any ideas? I've asked over at the CB750 forums as well.

I know the bike runs well, carbs are the only issue. Should I just scrap 'em and get a set of:

  • Murray's Carbs (Mikuni VM 34's)
  • Dynoman's (CR 31)
  • Cycle X's (Mikuni RS)

and move on from the horrid CV carbs?
1 - 1 of 9 Posts
check the ignition timing. if it's electronic and the gap is too small or it's a bit advanced they can hang onto the advance which makes rpm and that stops them returning. don't just assume it's a carb problem.

if its smelly it might also be lean - poor combusiton smells much the same.
1 - 1 of 9 Posts
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